Luminosity distribution of clusters with respect to redshift, class, and richness. Left panel: luminosity-redshift distribution of the clusters and groups identified in the point source sample based on their class. A 2σ detection limit is applied on the luminosities. The flux limit for the extent-selected sample of 1.5 × 10⁻¹⁴ ergs s⁻¹ cm⁻² is displayed as the dashed red line (Liu et al. 2022a). The luminosity of most clusters in the point source catalog is lower than that of the extent-selected sample, indicating that this sample is composed of clusters and groups that are smaller in extent and lower in mass, whose emission might be dominated by the central AGN. Right panel: X-ray luminosity as a function of the red-sequence richness. The blue data points show the extent-selected sample (Liu et al. 2022a; Klein et al. 2021). The orange points mark the clusters in the point source sample.